LONDON, England (CNN) -- A London-based student has designed a shoe insole that can monitor and control how much television a child watches, based on how much exercise they do in a day.

The "Square Eyes" insole has two small buttons, one that tracks how many steps a child has traveled and one that converts it into television watching credits.

The more a child exercises, the more time they can spend watching TV.

It calculates the time earned and once it runs out, the TV automatically switches itself off until more exercise is done.

The insole does this by communicating with a "base station," an intermediary device between the button in the shoe and the television set, which uses a radio signal to calculate and transmit the information.

The base station has an LCD screen, which displays how much watching time the wearer has in credit.

Square Eyes is the brainchild of Gillian Swain, a final year design student at Brunel University, in west London.

The main aim of the device, says Swain, is to combat child obesity.

The two "buttons," are both small and the wearer cannot feel them. They are hidden between the insole and base of the show.

Swain says two hours each day is the maximum recommended time a child should watch television.

The optimal steps traveled is 12,000 for girls and 15,000 for boys, which means roughly 15 minutes of television time is earned by traveling 1,500 steps.

"Today's children are exposed to a raft of television programs and children's channels. Ten years ago, children were entertained by playing games with their friends, now they are cooped up in their bedrooms watching hours of television programs," Swain says.

"Square-eyes will help children to include exercise in their daily routines from an early age."

Obesity is on the rise in the United Kingdom. In 1995, 9.9 per cent of children aged between two and 10 were classified as obese. This rose to 13.7 percent in 2003.

Paul Turnock, design director at Brunel's School of Engineering and Design, said the device had real potential to get children to be more active.

"Square-eyes will raise awareness amongst the family of their sedentary lifestyle and bring about a change in behavior of the whole family."